The Console Proxy is a type of System Virtual Machine that has a role in presenting a console view via the web UI. It connects the user’s browser to the VNC port made available via the hypervisor for the console of the guest. Both the administrator and end user web UIs offer a console connection.
Clicking on a console icon brings up a new window. The AJAX code downloaded into that window refers to the public IP address of a console proxy VM. There is exactly one public IP address allocated per console proxy VM. The AJAX application connects to this IP. The console proxy then proxies the connection to the VNC port for the requested VM on the Host hosting the guest. .
The hypervisors will have many ports assigned to VNC usage so that multiple VNC sessions can occur simultaneously.
There is never any traffic to the guest virtual IP, and there is no need to enable VNC within the guest.
The console proxy VM will periodically report its active session count to the Management Server. The default reporting interval is five seconds. This can be changed through standard Management Server configuration with the parameter consoleproxy.loadscan.interval.
Assignment of guest VM to console proxy is determined by first determining if the guest VM has a previous session associated with a console proxy. If it does, the Management Server will assign the guest VM to the target Console Proxy VM regardless of the load on the proxy VM. Failing that, the first available running Console Proxy VM that has the capacity to handle new sessions is used.
Console proxies can be restarted by administrators but this will interrupt existing console sessions for users.
The console viewing functionality uses a dynamic DNS service under the domain name realhostip.com to assist in providing SSL security to console sessions. The console proxy is assigned a public IP address. In order to avoid browser warnings for mismatched SSL certificates, the URL for the new console window is set to the form of https://aaa-bbb-ccc-ddd.realhostip.com. Customers will see this URL during console session creation. CloudStack includes the realhostip.com SSL certificate in the console proxy VM. Of course, CloudStack cannot know about DNS A records for our customers' public IPs prior to shipping the software. CloudStack therefore runs a dynamic DNS server that is authoritative for the realhostip.com domain. It maps the aaa-bbb-ccc-ddd part of the DNS name to the IP address aaa.bbb.ccc.ddd on lookups. This allows the browser to correctly connect to the console proxy's public IP, where it then expects and receives a SSL certificate for realhostip.com, and SSL is set up without browser warnings.
